Objective To analyze vitamin D concentration and its association with body composition of children in Huairou district of Beijing, to provide evidence for evaluation and improvement of nutritional status of vitamin D in children. Methods Totally, 381 children aged 7-11 years were recruited in Huairou district of Beijing(40.3°N). Samples of overnight fasting venous blood (drawn between 0630 and 0900) were obtained in late March. Serum 25-hydroxyvitamin D [25(OH)D] concentration was determined by ELISA kits (IDS Ltd, UK). Body composition indices of the whole body, the distal and proximal forearm were measured using dual-energy X-ray absorptiometry (DEXA, Norland, US A). Results The average serum 25 (OH) D concentration of all subjects was (44.4±12.5) nmol/L. The percentage of vitamin D insufficient [serum 25(OH) D≤ 50 nmol/L ] reached as high as 68.5% (261 people). The 25 (OH) D concentration of boys (46.3 nmol/L± 13.3 nmol/L) was significantly higher than that of girls (42.0 nmol/L±11.1 nmol/L), (t=3.38,P< 0.01). Between the serum 25(OH)D concentration and lean body mass of proximal forearm, distal forearm, whole body, and four limbs, significant positive correlations (r=0.13-0.19,P<0.05) were observed. After age, gender, height and weight were under controlled for, correlations between the serum 25(OH)D concentration and lean body mass at proximal forearm, and the two lower limbs still existed (r=0.12-0.14,P<0.05). The serum 25(OH)D concentration, the percentage of body fat at proximal forearm, and distal forearm were negatively correlated (r=-0.14, P<0.05;r=-0.11, P< 0.05). However, after adjusting for confounding effects, this correlation disappeared. No significant correlation between the serum 25 (OH)D concentration and body fat was observed at any position. Conclusion Vitamin D deficiency was common in children of suburb area of Beijing. Vitamin D status was positively associated with the lean body mass.

BACKGROUND: Before iodination of Swedish table salt in 1936, iodine deficiency resulting in goitre and hypothyroidism was common. Sweden has become iodine sufficient, as shown in a national survey in 2007, proving its iodination fortification programme effective for the general population. The objective of this study was to collect drinking water from water treatment plants nationally and test if water iodine concentration (WIC) correlated to urinary iodine concentration (UIC) of school-aged children in a national survey 2007 to former goitre frequency in 1929 and to thyroid volume data in 2007. METHODS: In 2012, 166 treatment plants, located in 57% (166 of 290) of all Swedish municipalities, were asked to collect drinking water samples of approximately 10 ml. In 2007, tap water samples of the same volume were collected from 30 randomly selected schools for the national survey. Analysis of WIC was done in both treatment plants in 2012 (n = 166) and tap water in 2007 (n = 30). The correlation of WIC to the children's UIC and thyroid volume after iodination was tested based on data from the national survey in 2007. The association of WIC to former goitre frequency was tested based on pre-iodination data, derived from a map of goitre frequency drawn in 1929. RESULTS: The median WIC from water treatment plants was 4.0 μg/L (range 0-27 μg/L). WIC was similar in coastal and inland areas, for both ground and surface water. WIC correlated with historical goitre areas and was lower in the goitre areas than in non-goitre areas (p < 0.001). WIC in the same municipalities as the schools correlated with the UIC of children (p < 0.01), but not with their thyroid volume. CONCLUSIONS WIC still contributes to iodine nutrition in Sweden, but iodination overrides the goitre effect.
Adolescent ; Child ; Drinking Water ; chemistry ; Female ; Food, Fortified ; analysis ; Goiter ; epidemiology ; history ; History, 20th Century ; History, 21st Century ; Humans ; Iodine ; analysis ; urine ; Male ; Sodium Chloride, Dietary ; analysis ; Sweden ; epidemiology ; Thyroid Gland ; anatomy & histology